The present invention is a new thermodynamic cycle and engine for motive power, such as for automobiles, and is designed to help relieve pressing problems of fuel availability and environmental pollution.
It has become evident that future stability of fuel supplies will require a diversity of energy sources. It is also evident that, if an automobile engine is developed which can cleanly and efficiently burn a diversity of renewable fuels, then the development of such fuels will be encouraged. Finally, it is evident that, to re-establish an equilibrium biosphere, man-made pollutants must be reduced to below natural background levels.
Because transportation consumes about 25 percent of our nonrenewable fuel resources and, in some areas, generates most of the air pollution, it is evident that the internal combustion engine, both gasoline and diesel, must eventually be replaced. The main replacement candidates are the Rankine and Stirling external combustion engines, and the regenerative gas turbine. The gas turbine requires exotic materials and has rather low efficiency. The Stirling engine, although efficient at full power, also requires exotic materials, is very expensive and heavy, and has poor transient response. The Rankine cycle holds the greatest promise primarily because it has great thermodynamic flexibility and need not require exotic materials.
Recently-developed automotive Rankine engines have been large, heavy, and inefficient mainly because the thermodynamic cycles used resembled simplified versions of electric-generating plant cycles or were adopted from early vehicular steam engines. The thermodynamic cycle and engine presented in this disclosure is specifically tailored to vehicular applications, although it is also suitable to marine use and to small-scale electric-generation units.